pyrimethamine

What is the most important information I should know about pyrimethamine?

What is pyrimethamine?

Pyrimethamine is an antiparasite medicine that helps prevent parasites from growing and reproducing in the body.

Pyrimethamine is used in adults and children to treat or prevent certain types of malaria. However, pyrimethamine is generally not preferred as a medicine to prevent malaria while traveling. When used to treat malaria, pyrimethamine should be used together with a faster-acting anti-malaria medicine such as chloroquine or quinine.

Pyrimethamine is also used to treat toxoplasmosis, an infection caused by the Toxoplasma parasite.

Pyrimethamine may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking pyrimethamine?

• a blood cell disorder called megaloblastic anemia that has been caused by folate (folic acid) deficiency.

To make sure pyrimethamine is safe for you, tell your doctor if you have ever had:

• seizures (especially if you take phenytoin);
• liver disease;
• kidney disease;
• alcoholism; or
• if you are malnourished.

In some cases, pyrimethamine is given to pregnant women to treat toxoplasmosis. Talk with your doctor about the risks and benefits of using this medicine if you are pregnant.

How should I take pyrimethamine?

Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Your dosage and the length of time you take pyrimethamine will depend on the reason you are taking this medicine. In some cases pyrimethamine is taken for several weeks, and you may need to take the medicine only once per week.

The pyrimethamine dose for treating toxoplasmosis is much higher than the dose for malaria.

Your dose may need to be cut in half after you have been taking pyrimethamine for 1 to 3 weeks (after 2 to 4 days for a child).

Pyrimethamine is often given in combination with other medications. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice.

While using pyrimethamine, you may need frequent blood tests.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Overdose symptoms may include stomach pain, severe vomiting, coughing up blood or vomit that looks like coffee grounds, feeling anxious or excited, seizure (convulsions), and weak or shallow breathing (breathing may stop).

What should I avoid while taking pyrimethamine?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What are the possible side effects of pyrimethamine?

• sore throat, swelling in your tongue;
• pale skin, easy bruising, purple spots under your skin;
• the first sign of any skin rash, no matter how mild;
• blood in your urine;
• fever, cold or flu symptoms;
• new or worsening cough, fever, trouble breathing;
• irregular heartbeats;
• signs of folate deficiency --unusual tiredness, mood changes, feeling sick, mouth sores, stomach discomfort, loss of appetite;
• severe skin reaction --fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects may include:

• vomiting; or
• loss of appetite.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect pyrimethamine?

Tell your doctor about all your current medicines and any you start or stop using, especially:

• methotrexate;
• phenytoin; or
• a sulfa drug.

This list is not complete. Other drugs may interact with pyrimethamine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

Your pharmacist can provide more information about pyrimethamine.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

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